Archaeological evidence from Cloggs Cave in southeastern Australia demonstrates that the GunaiKurnai nation utilized the limestone cavern for spiritual rituals, healing, and curses over an extraordinary span of 25,000 years, according to a study published in Frontiers in Environmental Archaeology. Researchers analyzing microscopic plant remnants and ash layers found that spiritual practitioners meticulously selected and burned whole grasses inside the dark subterranean space across millennia.
Microscopic Plant Clues Uncover Millennia of Ritual Activity
Excavations carried out in 2019 and 2020 at Cloggs Cave—situated on a bluff near Buchan, Victoria—yielded thousands of microscopic silica structures known as phytoliths. According to Dr. Elle Grono, a postdoctoral researcher at the Australian National University and corresponding author of the study, phytoliths mostly accumulate where a plant decays. Because no natural light penetrates the cave interior, plants do not grow inside, meaning the microscopic remains were intentionally carried in by people or animals like possums.
Grono noted that the research team focused specifically on half-burnt phytoliths retrieved from ashy layers. These altered remnants provide definitive proof of human transport, whereas unburnt phytoliths could have entered via animal fur or scats. The excavations were requested by the GunaiKurnai Land and Waters Corporation, whose representatives collaborated closely on the research design, fieldwork, and analysis.
Did you know? Phytoliths are durable silica structures that form within plant tissues, allowing scientists to identify ancient vegetation long after the actual leaves, stems, and flowers have decomposed.
Stratified Ash Layers and a 2,000-Year-Old Standing Stone
Microscopic analysis of two excavation pits, measuring 1.5 meters and 2.3 meters deep, revealed 73 thin ash layers in the upper sections. Using optically stimulated luminescence and accelerator mass spectrometry carbon dating, researchers determined these layers were deposited between approximately 4,400 and 1,600 years ago. Deeper deposits pushed the timeline of human use back to 25,000 years.
Hidden among the ash was a striking artifact: a 28-centimeter-high standing stone. According to the research team, Old Ancestors intentionally placed the stone inside the cavern for ritual purposes around 2,000 years ago. Further macro-botanical evidence, including fat-smeared, trimmed wooden sticks from Casuarina trees found in older deposits, confirmed that multiple types of ceremonies involving woody plants took place over the site’s long history.
Selective Harvesting of Native Grasses
The research team identified 29 distinct types of phytoliths representing grasses, herbs, and woody plants. Grass remains dominated the samples, accounting for up to 97 percent of the total. These included Pooideae grasses favoring cool conditions, Panicoideae grasses thriving in humid environments, and drought-tolerant Chloridoideae grasses.
Despite a surrounding landscape rich in riparian forests and open woodlands before European settlement, the people visiting the cave bypassed most local species. Instead, they selectively gathered whole grasses—including stems, leaves, flowers, and roots—growing near the cave entrance. As much as 18 percent of the recovered phytoliths showed signs of burning or melting.
Professor Bruno David from Monash University, who co-led the excavations alongside the GunaiKurnai Land and Waters Corporation, stated that the repeated burning aligns with traditional GunaiKurnai practices. According to David, ash was historically used to perform magic and rituals, and to track the footsteps of incoming visitors, including spirit-beings.
Frequently Asked Questions
What is Cloggs Cave and where is it located?
Cloggs Cave is a limestone cavern on a bluff near Buchan in Victoria, southern Australia, recognized as part of the traditional lands of the GunaiKurnai nation.
How did researchers determine the age of the cave deposits?
Scientists used optically stimulated luminescence and carbon dating via accelerator mass spectrometry on phytolith-bearing ash layers.
What are phytoliths?
Phytoliths are microscopic silica bodies formed inside plant tissues that survive long after the plants decay, helping archaeologists reconstruct ancient environments and human activities.
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